Purification through repeated column chromatography over silica gel and Sephadex LH-20 of the ethanol extract of the stems of Cissus aralioides (Baker) Planch. resulted in the isolation of a new ceramide, aralioidamide A (1) along with five known compounds (2-6). Their structures were determined by the extensive analysis of their spectroscopic (1D and 2D NMR) and spectrometric data, and comparison with those reported in the literature. Aralioidamide A (1) displayed weak antibacterial activity (MIC = 256 μg/mL) against Bacillus subtilis, Staphylococcus aureus and Shigella flexneri and was inactive (MIC > 256 μg/mL) against the tested fungi.

Spatiotemporal control of cell division is essential for the growth and development of multicellular organisms. In plant cells, proper cell plate insertion during cytokinesis relies on the premitotic establishment of the division plane at the cell cortex. Two plant-specific cytoskeleton arrays, the preprophase band (PPB) and the phragmoplast, play important roles in division-plane orientation and cell plate formation, respectively1. Microtubule organization and dynamics and their communication with membranes at the cortex and cell plate are coordinated by multiple, mostly distinct microtubule-associated proteins2. How division-plane selection and establishment are linked, however, is still unknown. Here, we report members of the Arabidopsis IQ67 DOMAIN (IQD) family3 as microtubule-targeted proteins that localize to the PPB and phragmoplast and additionally reside at the cell plate and a polarized cortical region including the cortical division zone (CDZ). IQDs physically interact with PHRAGMOPLAST ORIENTING KINESIN (POK) proteins4,5 and PLECKSTRIN HOMOLOGY GTPase ACTIVATING (PHGAP) proteins6, which are core components of the CDZ1. The loss of IQD function impairs PPB formation and affects CDZ recruitment of POKs and PHGAPs, resulting in division-plane positioning defects. We propose that IQDs act as cellular scaffolds that facilitate PPB formation and CDZ set-up during symmetric cell division.

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

Alternative splicing provides a fundamental and ubiquitous mechanism of gene regulation. Stimuli-induced retention of introns introduces novel proteoforms with altered signalling output: full-length CPK28 blocks immune signalling, while a truncated variant, lacking calcium responsiveness, promotes it.

Plants adjust the balance between growth and defence using photoreceptors and jasmonates. Levels of active jasmonates are reduced in a phytochrome B-dependent manner by upregulation of a 12-hydroxyjasmonate sulfotransferase, leading to increase in shade avoidance and decrease in defence.

Jasmonic acid biosynthesis starts in chloroplasts and is finalized in peroxisomes. The required export of a crucial intermediate out of the chloroplast is now shown to be mediated by a protein from the outer envelope called JASSY.

Temperature is a major factor governing the distribution and seasonal behaviour of plants. Being sessile, plants are highly responsive to small differences in temperature and adjust their growth and development accordingly. The suite of morphological and architectural changes induced by high ambient temperatures, below the heat-stress range, is collectively called thermomorphogenesis. Understanding the molecular genetic circuitries underlying thermomorphogenesis is particularly relevant in the context of climate change, as this knowledge will be key to rational breeding for thermo-tolerant crop varieties. Until recently, the fundamental mechanisms of temperature perception and signalling remained unknown. Our understanding of temperature signalling is now progressing, mainly by exploiting the model plant Arabidopsis thaliana. The transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4) has emerged as a critical player in regulating phytohormone levels and their activity. To control thermomorphogenesis, multiple regulatory circuits are in place to modulate PIF4 levels, activity and downstream mechanisms. Thermomorphogenesis is integrally governed by various light signalling pathways, the circadian clock, epigenetic mechanisms and chromatin-level regulation. In this Review, we summarize recent progress in the field and discuss how the emerging knowledge in Arabidopsis may be transferred to relevant crop systems.

Bacterial wilts of potato, tomato, pepper, and or eggplant caused by Ralstonia solanacearum are among the most serious plant diseases worldwide. In this study, the issue of developing bactericidal agents from natural sources against R. solanacearum derived from plant extracts was addressed. Extracts prepared from 25 plant species with antiseptic relevance in Egyptian folk medicine were screened for their antimicrobial properties against the potato pathogen R. solancearum by using the disc‐zone inhibition assay and microtitre plate dilution method. Plants exhibiting notable antimicrobial activities against the tested pathogen include extracts from Acacia arabica and Punica granatum. Bioactivity‐guided fractionation of A. arabica and P. granatum resulted in the isolation of bioactive compounds 3,5‐dihydroxy‐4‐methoxybenzoic acid and gallic acid, in addition to epicatechin. All isolates displayed significant antimicrobial activities against R. solanacearum (MIC values 0.5–9 mg/ml), with 3,5‐dihydroxy‐4‐methoxybenzoic acid being the most effective one with a MIC value of 0.47 mg/ml. We further performed a structure–activity relationship (SAR) study for the inhibition of R. solanacearum growth by ten natural, structurally related benzoic acids.

Rove beetles of the genus Stenus produce and store bioactive alkaloids like stenusine (3), 3‐(2‐methylbut‐1‐enyl)pyridine (4), and cicindeloine (5) in their pygidial glands to protect themselves from predation and microorganismic infestation.The biosynthesis of stenusine (3), 3‐(2‐methylbut‐1‐enyl)pyridine (4), and cicindeloine (5) was previously investigated in Stenus bimaculatus, Stenus similis, and Stenus solutus, respectively. The piperideine alkaloid cicindeloine (5) occurs also as a major compound in the pygidial gland secretion of Stenus cicindeloides. The three metabolites follow the same biosynthetic pathway, where the N‐heterocyclic ring is derived from L‐lysine and the side chain from L‐isoleucine. The different alkaloids are finally obtained by few modifications of shared precursor molecules, such as 2,3,4,5‐tetrahydro‐5‐(2‐methylbutylidene)pyridine (1). This piperideine alkaloid was synthesized and detected by GC/MS and GC at a chiral phase in the pygidial glands of Stenus similis, Stenus tarsalis, and Stenus cicindeloides.

A short survey of historic and current methods for the synthesis of selenocysteine, selenocystine, and derivatives and related compounds is presented, with an additional emphasis on the formation of selenocysteine‐derived SeS bridges. The majority of methods to the amino acid starts with protected and O ‐activated serine, but also other concepts are included such as radical or multicomponent strategies, the latter allowing also direct access to peptoids in one pot. Of special importance is the monomeric oxidative cyclization of selenocysteine–cysteine peptides to eight‐membered and larger rings with a selenenylsulfide bridge, a crucial element in several selenoproteins.